Caltech News tagged with "LIGO"http://www.caltech.edu/news/tag_ids/38/rss.xml
enSimulating Milliseconds of Stellar Collapse: A Conversation with Christian Otthttp://www.caltech.edu/news/simulating-milliseconds-stellar-collapse-conversation-christian-ott-42677
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Cynthia Eller</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Ott-Christian_0605-NEWS-WEB.jpg?itok=NKs2XKl2" alt="" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Caltech Professor of Theoretical Astrophysics Christian Ott</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Lance Hayashida</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Theoretical astrophysicists infer what sort of physical processes might cause the observed behavior of the universe; observational astrophysicists—astronomers—observe the universe to determine what is out there and how it is behaving.</p><p>Theoretical and observational astrophysics overlap more often than you might think. Astrophysicists with their varying specializations are in constant conversation with one another, weighing theory against observation and vice versa. Certainly this is true in the area of gravitational waves, first theorized by Albert Einstein nearly a hundred years ago as part of his general theory of relativity. While gravity is weak compared to other forces in the universe, gravitational waves actually squeeze and ripple space-time, creating physical effects in the universe that have not been successfully explained by any other mechanism.</p><p>There is excellent observational evidence for the existence of gravitational waves, including the behavior of the Hulse-Taylor pulsar, a binary system first discovered in 1974, and the recent finding by Caltech professor <a href="http://www.caltech.edu/content/building-bicep2-conversation-jamie-bock">Jamie Bock</a> and his coauthors that the cosmic microwave background has <a href="http://www.caltech.edu/content/bicep2-discovers-first-direct-evidence-inflation-and-primordial-gravitational-waves">a polarization pattern</a> specific to the gravitational waves that would have been released during the period of rapid inflation at the beginning of the universe. As of today, however, gravitational waves have not been directly detected, though not for want of trying. The Laser Interferometer Gravitational-wave Observatory (<a href="http://www.ligo.caltech.edu/">LIGO</a>), a collaboration between Caltech and the Massachusetts Institute of Technology, is currently being refitted with a new technology called <a href="https://www.advancedligo.mit.edu/">Advanced LIGO</a>. When Advanced LIGO goes online in 2015, there is hope that it will be able to directly detect gravitational waves as they come to the earth.</p><p><a href="http://www.tapir.caltech.edu/~cott/">Christian Ott</a>, professor of theoretical astrophysics at Caltech, is eagerly awaiting data from Advanced LIGO. Ott formulates scenarios for what happens when stars collapse, and one result of stellar collapse is the rapid release of gravitational waves, just the kind that LIGO hopes to detect.</p><p>Much about the collapse of massive stars is well understood. But there are crucial hundreds of milliseconds in this process that determine whether a star will collapse into a black hole or into a neutron star, and these milliseconds are still a matter of highly educated and informed speculation. It is these fractions of a second that consume Ott's interest. His <a href="supernova-or-not-supernova-3-d-model-stellar-core-collapse">scenarios for stellar collapse</a> are stories told with multiple terabytes of computer memory and petaflops of computing power—stories that are plausible, but whose truth is still unknown. One day detections of gravitational waves will help to confirm or contradict the models of stellar collapse that Ott is creating.</p><p><strong>How did you get interested in astrophysics?</strong></p><p>I've had an interest in this since I was a child growing up near Frankfurt, Germany. My father was an amateur astronomer. We had a small telescope at home, and we would look at the stars and the planets and the moon. After high school I chose to go to Heidelberg University to study physics and astronomy. As a freshman I read a book by <a href="http://www.its.caltech.edu/~kip/">Kip Thorne</a> (Richard P. Feynman Professor of Theoretical Physics, Emeritus) in German translation: <em>Black Holes and Time Warps.</em> He has a way of explaining these things so that even a layperson can understand them, and I became fascinated with black holes, neutron stars, and regions of strongly curved space-time. Honestly, Caltech seemed to me to be some mythical place. I wasn't even daring to dream about a place like this, and now I'm a professor here. It seems crazy to me.</p><p><strong>What spurred your interest in gravitational waves?</strong></p><p>Heidelberg University has an exchange program with the University of Arizona, so I came to spend a year there during college. Shortly after I arrived, I was telling a graduate student about my interest in neutron stars and black holes, and he recommended that I talk to Professor Adam Burrows, now at Princeton University. I wasn't too excited about gravitational waves at that point. I remember that quite well. But Professor Burrows set me to work on calculating gravitational waves from supernovae. That was 2001, and I've been working on similar questions ever since.</p><p><strong>What do you find exciting about supernovae?</strong></p><p>What most people don't realize is that without supernova explosions, we wouldn't be here.</p><p>There are two kinds of supernova explosions. Type Ia, those that come from white dwarf stars, are responsible for about 80 percent of the iron in the universe, and core-collapse supernovae, or Type II, which come from massive stars, are responsible for the remaining 20 percent of the iron. Without supernovae, there wouldn't be iron for our blood; there wouldn't be iron in Earth's core; there wouldn't be iron to make steel. Type II supernovae are also responsible for most of the oxygen and carbon in the universe. Without this enrichment of heavy elements, there would be no life, there would be no planets . . . it would be a pretty boring place.</p><p>So blowing stuff up and chemically polluting the universe, as supernovae do, is crucially important. But for fundamental physics, it's actually more interesting to examine the collapse itself.</p><p>The physics of stars up to that time is pretty well understood: we know where the pressure comes from in the iron core of a star; we know about thermonuclear reactions. However, as a star collapses the core becomes unbelievably dense. Eventually the electrons, which are exerting pressure in the opposite direction of gravity, are themselves squeezed out in a process called electron capture. In electron capture, a proton and an electron combine to make a neutron and a neutrino, a tiny subatomic particle with no electrical charge. When all of the neutrons and protons are packed together that tightly, the nuclear force kicks in. Usually the nuclear force binds protons and neutrons together, but when you try to squeeze protons and neutrons too close to one another, the nuclear force acts in the opposite direction: it has the effect of an outward pressure against the gravitational pull of a collapsing star. We don't understand this mechanism very well, but if we didn't have the nuclear force, all stars would collapse to black holes. There would be no neutron stars or supernovae. As it is, there are three outcomes we know of when stars collapse: Stars can collapse directly into black holes with no supernova; they can experience a weak supernova and a collapse into a neutron star that then collapses into a black hole within hours or days; or there can be a strong supernova that leaves a neutron star behind, apparently forever.</p><p><strong>What determines whether stellar collapses result in neutron stars rather than black holes?</strong></p><p>You tell me.</p><p><strong>You don't know?</strong></p><p>It's what we call "an area of active research." Advanced LIGO should help us to answer this question. When you see supernovae with telescopes, you're looking at optical waves, and these come pretty late in the process of stellar collapse; it's not easily connected to what's actually happening deep inside the star. A star collapse is a highly energetic event and should create substantial gravitational waves. When we detect gravitational waves, we will get information about what is going on earlier in the process. Depending on the precise shape—the amplitudes and frequencies—of the gravitational waves we detect, we can get a finer sense of exactly what is happening in the core of a star when it collapses.</p><p>Gravitational waves would arrive on Earth up to a day before we would see the light from the supernova, depending on how far away from us the supernova occurs. The same is true of neutrinos. Although neutrinos are remarkably tiny, a supernova produces an enormous quantity of neutrinos that fly out into the universe. When a star collapses, 99 percent of the gravitational energy released goes into neutrinos; only a tiny portion of the remainder takes the form of gravitational waves. We can already detect neutrinos on Earth, and we have even detected them directly from a supernova in 1987 that occurred in the Large Magellanic Cloud, a neighbor galaxy of our Milky Way. If a stellar collapse occurs anywhere near us, we should detect tens of thousands of neutrinos.</p><p><strong>So if you detected these specific gravitational waves or a lot of neutrinos, you could alert the entire scientific community to point their telescopes at the sky the next day to see the supernova?</strong></p><p>No! I would tell everyone to turn their big telescopes away, so the instruments would not be destroyed! Imagine if Betelgeuse blows up in a supernova—it's a red supergiant star twenty times the mass of the sun. If that goes, it's going to be as bright as the full moon for an entire month. At the very least, astronomers would need to put filters on their telescopes to protect them from the intense light.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/content/supernova-or-not-supernova-3-d-model-stellar-core-collapse" class="pr-link">To Supernova or Not to Supernova: A 3-D Model of Stellar Core Collapse</a></div><div class="field-item odd"><a href="http://www.caltech.edu/content/simulation-3-dimensional-magnetorotational-core-collapse" class="pr-link">Slideshow: Simulation of a 3-Dimensional Magnetorotational Core Collapse</a></div></div></div>Thu, 01 May 2014 19:55:34 +0000celler42677 at http://www.caltech.eduBuilding the World's Most Sensitive Detectors: A Conversation with Rana Adhikarihttp://www.caltech.edu/news/building-worlds-most-sensitive-detectors-conversation-rana-adhikari-40836
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Cynthia Eller</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Adhikara-Rana_7543-NEWS-WEB_1.jpg?itok=r0Sht9fv" alt="" /><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Lance Hayashida</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p><em>Caltech professor of physics Rana Adhikari has been on a singular quest for 15 years: to detect gravitational waves.</em></p><p><em>Gravitational waves—ripples in the fabric of space-time—are predicted by Einstein's theory of general relativity. Major astrophysical events such as the collapse of a binary system of neutron stars or black holes or one of each should release intense gravitational waves in the frequency range that we potentially might detect here on Earth. As theorized, gravitational waves are curious things; they move across the universe at the speed of light and pass right through everything they encounter without being affected as electromagnetic waves (such as light and radio waves) would be. And yet they are very weak compared to electromagnetic waves.</em></p><p><em>Scientists began to search for gravitational waves at the end of the 1960s, trying out a variety of technologies, including metal or ceramic bars that were designed to resonate at the proper frequencies when struck by gravitational waves. By the 1990s, the technology of choice was the laser interferometer, an L-shaped apparatus with two vacuum pipes four feet in diameter through which a laser beam passes. The laser's job is to sense the slightest motion in large glass mirrors hung at the far end of each pipe. Today the LIGO (Laser Interferometry Gravitational-Wave Observatory) project, a cooperative venture between Caltech and the Massachusetts Institute of Technology funded by the National Science Foundation, operates two laser interferometers whose vacuum pipes are four kilometers long: one in Livingston, Louisiana, and the other in Hanford, Washington. The detectors are currently offline while Advanced LIGO, slated to begin operation in 2014, is fitted into the apparatus.</em></p><p><em>So far the number of gravitational waves we have directly observed is zero.</em></p><p><em>Professor Adhikari, and indeed the entire LIGO team, is devoted to changing that tally in our favor. Adhikari recently sat down to answer a few questions about his work on LIGO and his experience of the students, staff, and faculty at Caltech.</em></p><p><strong>How did you get started with the search for gravitational waves?</strong></p><p>Whoever recruits you into this field says, "This is the best time to get in. You're getting in on the ground floor! The past has been a hard slog, but this is the perfect moment. In the next couple of years, boom! It's all going to play out." I heard that and thought, "Oh yes, I believe you. This is a great deal for me."</p><p>Now I say the same thing to potential recruits, but now it's true!</p><p><strong>How do you feel about the fact that gravitational waves still haven't been detected?</strong></p><p>It can be frustrating. Other astronomers have it a lot easier. Every time they point an instrument at the sky, they detect something. Meanwhile, LIGO has been waiting decades for anything, just one little blip. I went to an astronomy conference in San Francisco a while ago, and I swear, every single person who got up to give a talk said, "For six months we worked on this machine, and then we put it in a remote place in Africa or Chile, and as soon as we did, we saw this pulsar and this explosion. It was wonderful!" When I got up to give my talk, I pounded on the podium for a while and said, "What about me? I've been working on this thing for 15 years, and I've got nothing. Where's my signal?" People came up afterward and patted me on the back and said, "It's all right, it's going to happen for you too, don't worry."</p><p><strong>Do you think you will eventually detect gravitational waves?</strong></p><p>Yes, if our device is as sensitive as we believe it is, and if the kind of dramatic events that produce significant gravitational waves happen often enough.</p><p>I have extremely high confidence that these events are happening. In 1974, two radio astronomers, Russell Hulse and Joe Taylor, then at the University of Massachusetts at Amherst, observed a binary neutron-star system from a radio observatory in Puerto Rico. They and others have been tracking it ever since. The orbit of the stars is gradually decaying, which indicates the presence of gravitation. But more importantly, the decay is <em>exactly</em> as predicted by Einstein's theory. And we know that there are other events like this that would produce gravitational waves. People observe some such events using radio astronomy and optical astronomy. What we don't know is precisely how often they happen.</p><p><strong>And you believe that if they happen, LIGO will detect them?</strong></p><p>I think the main reason we stick with this effort is because our detectors are working like they should be. We can see a big piece of glass—a 40-kilogram mirror—move back and forth a distance equivalent to one-billionth the size of a hydrogen atom in response to a gravitational wave. You might say it could move by the size of a hydrogen atom and be believed. But one-billionth? Come on. It seems like this level of sensitivity can't be possible. When you tell people how sensitive LIGO is, it sounds like you're a nutcase—but we've measured it to be that precise.</p><p><strong>With an instrument that sensitive, how do you avoid measuring everything else?</strong></p><p>LIGO reacts to everything. If there's a lightning strike in Kansas, we see a magnetic pulse; if there's an earthquake anywhere in the world, our detector shakes around. Once, we had interference in our signal at the LIGO site in eastern Washington, and it was due to the release of a little extra water by a dam in <em>western</em> Washington.</p><p>Our whole concept is to get a thousand different kinds of sensors attached to LIGO: accelerometers, magnetometers, microphones, pressure sensors, devices to measure temperature, cosmic rays, everything. Our detector is the only thing in the world that will ever sense a gravitational wave, because it is so hard to detect. So if you see a blip in any <em>other</em> sensor, you're seeing something other than a gravitational wave.</p><p><strong>Are you working to further increase the sensitivity?</strong></p><p>All the time. For example, we originally decided to go with glass—fused silica—as the material for the mirrors. People have been studying glass for hundreds of years; it has some almost magical properties that may help LIGO to detect gravitational waves.</p><p>More recently we've learned that there may be an even quieter material: silicon crystal. Silicon has some difficult properties, but they vanish at about 120 degrees Kelvin, or about minus 150 degrees centigrade. So now we are looking at developing silicon detectors and keeping them in a cryogenic atmosphere. Unfortunately, this means completely revamping LIGO. So while the next generation of LIGO—Advanced LIGO—is online, we will already be working on its successor.</p><p><strong>How are students involved in your work on LIGO?</strong></p><p>From the beginning, I thought that if we were going to make LIGO work, we had better get a huge gang of students from Caltech working on this project. That's what makes it all go. My students work from . . . well, sometime after lunch until the sun rises. Starting several years ago, we set students to work on prototyping new, speculative ideas for LIGO. Some of these ideas never add up to anything, but others that we originally thought wouldn't be of any use at all are now the standard vanilla technology of LIGO. We ask ourselves, "How did we ever live without this?"</p><p>One of these student projects was to imagine putting a bunch of microphones and vibration sensors around LIGO. Then, without trying to determine which events were creating which reactions, we simply inputted the signals into a computer and told it to subtract the noise out of the interferometer. We found out that there were already learning algorithms like this created by people for other reasons. In fact, to get rid of all kinds of noise in the interferometer we now use similar learning algorithms to those used in noise-canceling headphones.</p><p>We have international collaborators in Japan, Italy, France, Germany, Australia, and India, so we always have undergraduate and graduate students coming from these places. Our labs are an international mix of people of different ages and levels. And everyone is really into the project. I don't have to do any cheerleading; they're already self-motivated.</p><p><strong>What excites you about Caltech?</strong></p><p>Getting to work with the people here. They're all really bright and energetic and thinking about things all the time. Before physics, I had several other jobs, and mostly we tried to figure out how to do the least possible amount of work until five o'clock came around and we could get out. Here the work is so exciting that you can easily lose track of time and leave six hours late.</p><p>Caltech is a special place because of its intensity, and also because of all the expertise that is around. We have geophysics, aeronautics, applied physics . . . And the teaching is wonderful. For the past three years I have taught electromagnetism to nonphysics majors. It's full of practical questions like "What is this thing?" I learn a lot from teaching that.</p></div></div></div>Mon, 28 Oct 2013 23:20:59 +0000celler40836 at http://www.caltech.eduNew LIGO Executive Director Namedhttp://www.caltech.edu/news/new-ligo-executive-director-named-1715
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kathy Svitil</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/CT_LIGO-Director_SPOTLIGHT.jpg?itok=4tSF9hm7" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.—David Reitze has been named executive director of the Laser Interferometer Gravitational-Wave Observatory (LIGO), designed and operated by the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology (MIT), with funding from the National Science Foundation (NSF). Reitze has also been named a senior research associate at Caltech.</p><p class="MsoNormalCxSpMiddle">A professor of physics at the University of Florida, Gainesville, and a visiting associate at Caltech since 2007, Reitze will succeed the retiring Jay Marx. Marx, a senior research associate in physics at Caltech, served as executive director since 2006 and will continue to work on LIGO part-time.</p><p>"I'm really excited about joining the LIGO laboratory and Caltech and serving in the role of executive director," says Reitze, who received his PhD from the University of Texas at Austin in 1990 and has been involved in the LIGO project since 1996. His early research focused on ultrafast optics and the development of high-power optical components and ultrafast lasers. More recently, he led the design effort for the input optics of Advanced LIGO, a more sensitive incarnation of the detector slated to begin operation in 2014. "In addition to the incredible science that LIGO will do, one of the main reasons I accepted the position was the outstanding quality and commitment of the LIGO laboratory staff," he says.</p><p class="MsoNormalCxSpMiddle">LIGO was originally proposed decades ago as a means of detecting gravitational waves. Gravitational waves are ripples in the fabric of space and time—produced by massive accelerating objects such as black-hole and neutron-star collisions—which propagate outward through the universe. They were first predicted in 1916 as a consequence of Albert Einstein's general theory of relativity.</p><p class="MsoNormalCxSpMiddle">Each of the L-shaped LIGO interferometers (including 4-km detectors in Hanford, Washington, and Livingston, Louisiana) use a laser split into two beams that travel back and forth down long arms (which are beam tubes from which the air has been evacuated). The beams are used to monitor the distance between precisely con<a name="_GoBack" id="_GoBack"></a>figured mirrors. According to Einstein's theory, the relative distance between the mirrors will change very slightly when a gravitational wave passes by. </p><p class="MsoNormalCxSpMiddle">LIGO research is carried out by the LIGO Scientific Collaboration (LSC), a group of 840 scientists at universities around the United States and in 13 other countries; Reitze served as the LSC spokesperson from 2007 to 2011.</p><p class="MsoNormalCxSpMiddle">The LSC network includes the LIGO interferometers and the GEO600 interferometer, a project located near Hannover, Germany, and designed and operated by scientists from the Max Planck Institute for Gravitational Physics, along with partners in the United Kingdom funded by the Science and Technology Facilities Council (STFC). The LSC works jointly with the Virgo Collaboration—which designed and constructed the 3-km long Virgo interferometer located in Cascina, Italy—to analyze data from the LIGO, GEO, and Virgo interferometers.</p><p class="MsoNormalCxSpMiddle">The next major milestone for LIGO is Advanced LIGO, which will incorporate upgraded designs and technologies that have been developed by the LSC. The original configuration of LIGO was sensitive enough to detect a change in the lengths of the 4-km arms by a distance one-thousandth the size of a proton; Advanced LIGO, which will utilize the infrastructure of LIGO, will be 10 times more sensitive.</p><p class="MsoNormalCxSpMiddle">The increased sensitivity will be important because it will allow scientists to detect cataclysmic events such as black-hole and neutron-star collisions at 10-times-greater distances. And because LIGO can "see" in all directions, Advanced LIGO will be 1,000 times more likely to detect gravitational waves and will make important contributions to astronomy and physics.</p><p class="MsoNormalCxSpMiddle">"This is a great time in LIGO's history," Reitze says. "Over the past decade, we've demonstrated that we can build and operate the LIGO interferometers with truly exquisite sensitivity and use them to conduct scientifically interesting searches for gravitational waves. It's also an exciting time for worldwide gravitational-wave scientific community," he adds.</p><p class="MsoNormalCxSpMiddle">"We're really delighted to have Dr. Reitze take over the leadership of LIGO. He knows the project, the science, and the challenges, and is superbly qualified to lead the team in bringing the Advanced LIGO detector on line," says Tom Soifer, professor of physics, director of the Spitzer Science Center, and chair of the Division of Physics, Mathematics and Astronomy at Caltech. "Jay Marx set a high standard," he adds, "and Dave is fully ready to match that in leading LIGO in this most exciting time. We're looking forward to the first detections of gravitational waves from astronomical sources, and the new window on the universe it will provide."</p><p class="MsoNormalCxSpMiddle">"Once Advanced LIGO is running, we'll continue to work closely with our European colleagues at GEO600 and Virgo as part of the new and growing global gravitational-wave network," Reitze says. "The Large Cryogenic Gravitational Wave Telescope in Japan is scheduled to begin operation soon after Advanced LIGO, adding a fourth detector to the network. The global network will allow us to look at the underlying sources of gravitational waves in tandem with other types of astronomical telescopes—optical, radio, X-ray, gamma ray—to give a much better picture of the astrophysics of the most violent events in the universe."</p></div></div></div>Wed, 24 Aug 2011 14:00:00 +0000admin1715 at http://www.caltech.eduTMT and LIGO at the National Science Festivalhttp://www.caltech.edu/news/tmt-and-ligo-national-science-festival-1813
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Allison Benter</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/SAM_1023.jpeg?itok=Lj8lurgm" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>For two weeks in October, the National Mall and surrounding areas in Washington, D.C., were transformed into a city-size laboratory for exploration and education as part of the inaugural USA Science &amp; Engineering Festival—the nation's first national science festival.</p><p>Two Caltech-led projects—the Laser Interferometer Gravitational-Wave Observatory (LIGO) Science Education Center and the Thirty Meter Telescope project—hosted interactive science exhibits during the expo and helped inspire visitors young and old to think scientifically.</p><p>Over 500 of the nation's leading science and engineering organizations hosted more than 1,500 free, interactive exhibits that drew about 500,000 people to downtown Washington to learn about science, technology, engineering, and math. For those who couldn't make it to the capital, over 50 satellite events were sponsored throughout the nation.</p><p><a href="http://www.youtube.com/watch?v=lHY-mo1tgkM">Watch the video of festival visitors from TMT's Fisheye camera.</a></p></div></div></div>Tue, 02 Nov 2010 14:00:00 +0000lorio1813 at http://www.caltech.eduLISA Gravitational-Wave Mission Strongly Endorsed by National Research Councilhttp://www.caltech.edu/news/lisa-gravitational-wave-mission-strongly-endorsed-national-research-council-1640
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kathy Svitil</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/LISA-350.jpg?itok=dGzcUlkz" alt="" /><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: AEI/MildeMarketing/Exozet</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif. — The National Research Council (NRC) has strongly recommended the Laser Interferometer Space Antenna (LISA) as one of NASA's next two major space missions, to start in 2016 in collaboration with the European Space Agency (ESA). LISA will study the universe in a manner different from any other space observatory, by observing gravitational waves. The recommendation was announced August 13 in a press conference at the Keck Center of the National Academies in Washington, D.C. </p><p>In the just-concluded "Astro2010" decadal survey, a panel of experts was convened to look at the coming decade and prioritize all research activities in astronomy and astrophysics, as well as at the interface of these disciplines with physics. The survey recommended LISA highly because of the expectation that observations of gravitational waves in space will answer key scientific questions about the astrophysics of the cosmic dawn and the physics of the universe.</p><p>"We are very pleased with the NRC's recognition of LISA's extraordinary research opportunities in astrophysics and fundamental physics," says Tom Prince, professor of physics at the California Institute of Technology (Caltech), senior research scientist at the Jet Propulsion Laboratory (JPL), and the U.S. chair of the LISA International Science Team. Scientists from many European countries participate in LISA either as members of the science team or as members of the LISA International Science Community. "We are looking forward to unveiling a new window on the universe by observing thousands of gravitational wave sources." </p><p>"This recommendation and our excellent reputation in the scientific community encourages us a lot. With LISA we will open up an entirely new way of observing the universe, with immense potential to enlarge our understanding of physics and astronomy in unforeseen ways," says Karsten Danzmann, European chair of the LISA International Science Team.</p><p>"In the past it has sometimes been difficult to get mainstream astronomers to recognize the importance of gravitational wave astronomy," says Marcia Rieke, a professor of astronomy at the University of Arizona and vice chair for the Astro2010 subcommittee on programs. "The ranking of LISA is an indication that astronomers are recognizing the opportunities that LISA presents for using gravitational waves to study the universe in a new way." </p><p>"The science case for LISA has become much richer over the last 10 years. On the experimental side, a similar story could be made that what were once novel measurement concepts are now reliable, proven technologies," says LISA science team member Scott Hughes, associate professor of physics at the Massachusetts Institute of Technology. </p><p>"In the 13 years I've been involved with LISA, its technology and science have advanced beyond my wildest first dreams," says Sterl Phinney, professor of theoretical astrophysics at Caltech, current co-chair of the sources and data analysis working group of the LISA science team, and chair of the original LISA Mission Definition Team. "I'm looking forward to its precise measurements telling us if the giant black holes in the centers of galaxies really follow the rules of Einstein's theory of general relativity, and which if any of the ideas about how they get made are correct." </p><p>"This strong endorsement by America's leading astronomers makes it official: LISA has the potential to become one of the most important astronomical observatories of our time," says Bernard F. Schutz, director of the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Potsdam, Germany and co-chair of the sources and data analysis working group of the LISA science team. </p><p>"When LISA was adopted by the ESA in 1995, it was because its observations of gravitational waves would provide powerful insight into the fundamentals of gravity, of Einstein's theory and all its predictions," adds Schutz. "In the last 15 years, astronomers also have learned how LISA can open up hidden chapters in the history of the universe, by listening to the waves made by the very first stars, the earliest black holes, and by some of the oldest stars in existence today. By seeing how the waves from early black holes are stretched out as they move toward us through the expanding universe, LISA can even study the mysterious dark energy."</p><p>LISA is designed to be complementary to the ground-based observatories (the Laser Interferometer Gravitational-Wave Observatory, or LIGO, in the United States, and Virgo and GEO-600 in Europe) that currently are actively searching for signs of gravitational waves; both search for ripples in the fabric of space and time formed by the most violent events in the universe, such as the coalescence of black holes, that carry with them information about their origins and about the nature of gravity that cannot be obtained using conventional astronomical tools. The existence of the waves was predicted by Albert Einstein in 1916 in his general theory of relativity.</p><p>The LISA instrument will consist of three spacecraft in a triangular configuration with 5-million-kilometer arms (12.5 times the distance from the Earth to the moon), moving in an Earth-like orbit around the sun. Gravitational waves from sources throughout the universe will produce slight oscillations in the arm lengths (changes as small as about 10 picometers, or 10 million millionths of a meter, a length smaller than the diameter of the smallest atom). LISA will capture these motions—and thus measure the gravitational waves—using laser links to monitor the displacements of gold–platinum test masses floating inside the spacecraft. It is slated for launch in the early 2020s. </p><p>LISA will observe gravitational waves in a lower frequency band (0.1 milliHertz to 1 Hertz) than that detectable by LIGO and other ground-based instruments, which are designed to sense sources at frequencies above 10 Hertz.</p><p>Because gravitational waves are moving ripples in the curvature of space, and because LISA will sense ripples coming simultaneously from tens of thousands of sources in every direction, the instrument acts more like a microphone listening to sound than like a telescope or a camera taking a picture. This new kind of observing tells us directly about the motion of invisible masses, complementing traditional astronomical observations of light, which reveal only visible atoms.</p><p>In the U.S. the LISA project is managed by the NASA Goddard Space Flight Center and includes significant participation by JPL, which is managed by Caltech for NASA. </p><p>LISA's hardware will get its first test in space with the launch of LISA Pathfinder by 2013. This will include a thorough test of a crucial component of LISA's technology: drag-free operation, whereby the spacecraft shield the test masses from external disturbances by precisely monitoring their motions and moving around them to preserve their free fall. LPF recently reached a key phase of development, during which the flight hardware undergoes rigorous pre-flight testing.</p></div></div></div>Wed, 18 Aug 2010 06:00:00 +0000ksvitil1640 at http://www.caltech.eduLIGO Listens for Gravitational Echoes of the Birth of the Universehttp://www.caltech.edu/news/ligo-listens-gravitational-echoes-birth-universe-1561
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Results set new limits on gravitational waves originating from the Big Bang; constrain theories about universe formation</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kathy Svitil</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/s5004.jpg?itok=MULifhlC" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Pasadena, Calif.—An investigation by the LIGO (Laser Interferometer Gravitational-Wave Observatory) Scientific Collaboration and the Virgo Collaboration has significantly advanced our understanding of the early evolution of the universe.</p><p>Analysis of data taken over a two-year period, from 2005 to 2007, has set the most stringent limits yet on the amount of gravitational waves that could have come from the Big Bang in the gravitational wave frequency band where LIGO can observe. In doing so, the gravitational-wave scientists have put new constraints on the details of how the universe looked in its earliest moments.</p><p>Much like it produced the cosmic microwave background, the Big Bang is believed to have created a flood of gravitational waves—ripples in the fabric of space and time—that still fill the universe and carry information about the universe as it was immediately after the Big Bang. These waves would be observed as the "stochastic background," analogous to a superposition of many waves of different sizes and directions on the surface of a pond. The amplitude of this background is directly related to the parameters that govern the behavior of the universe during the first minute after the Big Bang.</p><p>Earlier measurements of the cosmic microwave background have placed the most stringent upper limits of the stochastic gravitational wave background at very large distance scales and low frequencies. The new measurements by LIGO directly probe the gravitational wave background in the first minute of its existence, at time scales much shorter than accessible by the cosmic microwave background.</p><p>The research, which appears in the August 20 issue of the journal <em>Nature</em>, also constrains models of cosmic strings, objects that are proposed to have been left over from the beginning of the universe and subsequently stretched to enormous lengths by the universe's expansion; the strings, some cosmologists say, can form loops that produce gravitational waves as they oscillate, decay, and eventually disappear.</p><p>Gravitational waves carry with them information about their violent origins and about the nature of gravity that cannot be obtained by conventional astronomical tools. The existence of the waves was predicted by Albert Einstein in 1916 in his general theory of relativity. The LIGO and GEO instruments have been actively searching for the waves since 2002; the Virgo interferometer joined the search in 2007.</p><p>The authors of the new paper report that the stochastic background of gravitational waves has <em>not</em> yet been discovered. But the nondiscovery of the background described in the <em>Nature</em> paper already offers its own brand of insight into the universe's earliest history.</p><p>The analysis used data collected from the LIGO interferometers, a 2 km and a 4 km detector in Hanford, Washington, and a 4 km instrument in Livingston, Louisiana. Each of the L-shaped interferometers uses a laser split into two beams that travel back and forth down long interferometer arms. The two beams are used to monitor the difference between the two interferometer arm lengths.</p><p>According to the general theory of relativity, one interferometer arm is slightly stretched while the other is slightly compressed when a gravitational wave passes by.</p><p>The interferometer is constructed in such a way that it can detect a change of less than a thousandth the diameter of an atomic nucleus in the lengths of the arms relative to each other.</p><p>Because of this extraordinary sensitivity, the instruments can now test some models of the evolution of the early universe that are expected to produce the stochastic background.</p><p>"Since we have not observed the stochastic background, some of these early-universe models that predict a relatively large stochastic background have been ruled out," says Vuk Mandic, assistant professor at the University of Minnesota.</p><p>"We now know a bit more about parameters that describe the evolution of the universe when it was less than one minute old," Mandic adds. "We also know that if cosmic strings or superstrings exist, their properties must conform with the measurements we made-that is, their properties, such as string tension, are more constrained than before."</p><p>This is interesting, he says, "because such strings could also be so-called fundamental strings, appearing in string-theory models. So our measurement also offers a way of probing string-theory models, which is very rare today."</p><p>"This result was one of the long-lasting milestones that LIGO was designed to achieve," Mandic says. Once it goes online in 2014, Advanced LIGO, which will utilize the infrastructure of the LIGO observatories and be 10 times more sensitive than the current instrument, will allow scientists to detect cataclysmic events such as black-hole and neutron-star collisions at 10-times-greater distances.</p><p>"Advanced LIGO will go a long way in probing early universe models, cosmic-string models, and other models of the stochastic background. We can think of the current result as a hint of what is to come," he adds.</p><p>"With Advanced LIGO, a major upgrade to our instruments, we will be sensitive to sources of extragalactic gravitational waves in a volume of the universe 1,000 times larger than we can see at the present time. This will mean that our sensitivity to gravitational waves from the Big Bang will be improved by orders of magnitude," says Jay Marx of the California Institute of Technology, LIGO's executive director.</p><p>"Gravitational waves are the only way to directly probe the universe at the moment of its birth; they're absolutely unique in that regard. We simply can't get this information from any other type of astronomy. This is what makes this result in particular, and gravitational-wave astronomy in general, so exciting," says David Reitze, a professor of physics at the University of Florida and spokesperson for the LIGO Scientific Collaboration.</p><p>"The scientists of the LIGO Scientific Collaboration and the Virgo Collaboration have joined their efforts to make the best use of their instruments. Combining simultaneous data from the LIGO and Virgo interferometers gives information on gravitational-wave sources not accessible by other means. It is very suggestive that the first result of this alliance makes use of the unique feature of gravitational waves being able to probe the very early universe. This is very promising for the future," says Francesco Fidecaro, a professor of physics with the University of Pisa and the Istituto Nazionale di Fisica Nucleare, and spokesperson for the Virgo Collaboration.</p><p>Maria Alessandra Papa, senior scientist at the Max Planck Institute for Gravitational Physics and the head of the LSC overall data analysis effort adds, "Hundreds of scientists work very hard to produce fundamental results like this one: the instrument scientists who design, commission and operate the detectors, the teams who prepare the data for the astrophysical searches and the data analysts who develop and implement sensitive techniques to look for these very weak and elusive signals in the data."</p><p>The LIGO project, which is funded by the National Science Foundation (NSF), was designed and is operated by Caltech and the Massachusetts Institute of Technology for the purpose of detecting gravitational waves, and for the development of gravitational-wave observations as an astronomical tool.</p><p>Research is carried out by the LIGO Scientific Collaboration, a group of 700 scientists at universities around the United States and in 11 foreign countries. The LIGO Scientific Collaboration interferometer network includes the LIGO interferometers and the GEO600 interferometer, which is located near Hannover, Germany, and designed and operated by scientists from the Max Planck Institute for Gravitational Physics, along with partners in the United Kingdom funded by the Science and Technology Facilities Council (STFC).</p><p>The Virgo Collaboration designed and constructed the 3 km long Virgo interferometer located in Cascina, Italy, funded by the Centre National de la Recherche Scientifique (France) and by the Istituto Nazionale di Fisica Nucleare (Italy). The Virgo Collaboration consists of 200 scientists from five Europe countries and operates the Virgo detector. Support for the operation comes from the Dutch—French—Italian European Gravitational Observatory Consortium. The LIGO Scientific Collaboration and Virgo work together to jointly analyze data from the LIGO, Virgo, and GEO interferometers.</p><p>The next major milestone for LIGO is the Advanced LIGO Project, slated to begin operation in 2014. Advanced LIGO will incorporate advanced designs and technologies that have been developed by the LIGO Scientific Collaboration. It is supported by the NSF, with additional contributions from the U.K.'s STFC and Germany's Max Planck Society.</p><p>The paper is entitled "An Upper Limit on the Amplitude of Stochastic Gravitational-Wave Background of Cosmological Origin."</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.ligo.caltech.edu" class="pr-link">LIGO</a></div></div></div>Thu, 20 Aug 2009 00:01:00 +0000ksvitil1561 at http://www.caltech.edu"Einstein's Cosmic Messengers" Multimedia Concert Inspired by Quest for Gravitational Waveshttp://www.caltech.edu/news/einsteins-cosmic-messengers-multimedia-concert-inspired-quest-gravitational-waves-1478
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Martin Voss</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Multimedia%20Concert_1.jpg?itok=-uGJB_vy" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.--Join two world-renowned California Institute of Technology (Caltech) physicists and an award-winning composer for the world premiere of "Einstein's Cosmic Messengers," an inventive multimedia concert. Inspired by Caltech's involvement with the Laser Interferometer Gravitational-wave Observatory (LIGO), the presentation takes an innovative approach to communicating scientific exploration and discovery to the general public. The event takes place Thursday, October 30, at 8 p.m., in Beckman Auditorium on the Caltech campus.</p><p>This unique event will feature noted physicist Kip Thorne, Feynman Professor of Theoretical Physics and LIGO cofounder; Jay Marx, LIGO executive director and senior research associate in physics; and Andrea Centazzo, award-winning composer, percussionist, and multimedia artist. The program is based on LIGO's quest for the detection of gravitational waves--ripples in the fabric of space and time produced by violent events in the distant universe. Albert Einstein predicted the existence of these waves in 1916. LIGO, which was designed by Caltech and MIT physicists, began its search in 2001 with funding from the National Science Foundation.</p><p>Thorne will open the program by explaining how gravitational waves can reveal the fundamental nature of gravity and open a new window onto the "warped" side of the universe, shining light on previously inaccessible events such as violent coalescences of black holes and neutron stars. Marx will follow with a discussion on the history, achievements, and promise of LIGO's search for gravitational waves. Centazzo will then perform his world premiere of "Einstein's Cosmic Messengers," the multimedia concert he created with Jet Propulsion Laboratory scientist Michele Vallisneri. The presentation blends music and sounds played live with images and animations inspired by LIGO's facilities, the universe, and Einstein's genius and obsessions, creating a one-of-a-kind live performance.</p><p>Vallisneri initially conceived the concert and Centazzo made it a reality. "'Einstein's Cosmic Messengers' is the result of exposing professional composer and video artist Andrea Centazzo to my narrative of the birth of astronomy and the great revolutions in our understanding of the cosmos," says Vallisneri. "The performance includes evocative images, projected on a cinema screen, complemented by synchronized music played live on a vast array of percussive instruments, both acoustic and digital.</p><p>"I hope the concert can expose the public, whether artistically or scientifically inclined, to the quest to measure gravitational waves, an extremely engaging intellectual and technological adventure that I work on every day. I love to see human creativity transcend the boundaries between science and the arts and humanities. This will be a breathtaking journey through magnificent visions of the universe."</p><p>Visit <a href="http://events.caltech.edu/events/event-5781.html">http://events.caltech.edu/events/event-5781.html</a>, <a href="http://www.ligo.caltech.edu">www.ligo.caltech.edu</a>, and <a href="http://www.andreacentazzo.com/ecm">www.andreacentazzo.com/ecm</a> for more information, including images and a sample video at Centazzo's site. Admission and parking are free. No tickets or reservations are required.</p></div></div></div>Fri, 24 Oct 2008 14:00:00 +00001478 at http://www.caltech.eduLIGO Observations Probe the Dynamics of the Crab Pulsarhttp://www.caltech.edu/news/ligo-observations-probe-dynamics-crab-pulsar-1436
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kathy Svitil</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/icon.jpg?itok=GVhgKwLm" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.-- The search for gravitational waves has revealed new information about the core of one of the most famous objects in the sky: the Crab Pulsar in the Crab Nebula. An analysis by the international LIGO (Laser Interferometer Gravitational-Wave Observatory) Scientific Collaboration to be submitted to Astrophysical Journal Letters has shown that no more than 4 percent of the energy loss of the pulsar is caused by the emission of gravitational waves.</p><p>The Crab Nebula, located 6,500 light years away in the constellation Taurus, was formed in a spectacular supernova explosion in 1054. According to ancient sources, including Chinese texts that referred to it as a "guest star," the explosion was visible in daylight for more than three weeks, and may briefly have been brighter than the full moon. At the heart of the nebula remains an incredibly rapidly spinning neutron star that sweeps two narrow radio beams across the Earth each time it turns. The lighthouse-like radio pulses have given the star the name "pulsar."</p><p>"The Crab Pulsar is spinning at a rate of 30 times per second. However, its rotation rate is decreasing rapidly relative to most pulsars, indicating that it is radiating energy at a prodigious rate," says Graham Woan of the University of Glasgow, who co-led the science group that used LIGO data to analyze the Crab Pulsar, along with Michael Landry of the LIGO Hanford Observatory. Pulsars are almost perfect spheres made up of neutrons and contain more mass than the sun in an object only 10 km in radius. The physical mechanisms for energy loss and the accompanying braking of the pulsar spin rate have been hypothesized to be asymmetric particle emission, magnetic dipole radiation, and gravitational-wave emission.</p><p>Gravitational waves are ripples in the fabric of space and time and are an important consequence of Einstein's general theory of relativity. A perfectly smooth neutron star will not generate gravitational waves as it spins, but the situation changes if its shape is distorted. Gravitational waves would have been detectable even if the star were deformed by only a few meters, which could arise because its semisolid crust is strained or because its enormous magnetic field distorts it. "The Crab neutron star is relatively young and therefore expected to be less symmetrical than most, which means it could generate more gravitational waves," says Graham Woan.</p><p>The scenario that gravitational waves significantly brake the Crab pulsar has been disproved by the new analysis.</p><p>Using published timing data about the pulsar rotation rate from the Jodrell Bank Observatory, LIGO scientists monitored the neutron star from November 2005 to August 2006 and looked for a synchronous gravitational-wave signal using data from the three LIGO interferometers, which were combined to create a single, highly sensitive detector.</p><p>The analysis revealed no signs of gravitational waves. But, say the scientists, this result is itself important because it provides information about the pulsar and its structure.</p><p>"We can now say something definite about the role gravitational waves play in the dynamics of the Crab Pulsar based on our observations," says David Reitze, a professor of physics at the University of Florida and spokesperson for the LIGO Scientific Collaboration. "This is the first time the spin-down limit has been broken for any pulsar, and this result is an important milestone for LIGO."</p><p>Michael Landry adds, "These results strongly imply that no more than 4 percent of the pulsar's energy loss is due to gravitational radiation. The remainder of the loss must be due to other mechanisms, such as a combination of electromagnetic radiation generated by the rapidly rotating magnetic field of the pulsar and the emission of high-velocity particles into the nebula."</p><p>"LIGO has evolved over many years to its present capability to produce scientific results of real significance," says Jay Marx of the California Institute of Technology, LIGO's executive director. "The limit on the Crab Pulsar's emission of gravitational waves is but one of a number of important results obtained from LIGO's recent two-year observing period. These results only serve to further our anticipation for the spectacular science that will come from LIGO in the coming years."</p><p>"Neutron stars are very hot when they are formed in a supernova, and then they cool rapidly and form a semisolid crust. Our observation of a relatively young star like the Crab is important because it shows that this skin, if it had irregularities when it first 'froze,' has by now become quite smooth," says Bernard F. Schutz, director of the Albert Einstein Institute in Germany.</p><p>Joseph Taylor, a Nobel Prize-winning radio astronomer and professor of physics at Princeton University, says, "The physics world has been waiting eagerly for scientific results from LIGO. It is exciting that we now know something concrete about how nearly spherical a neutron star must be, and we have definite limits on the strength of its internal magnetic field."</p><p>The LIGO project, which is funded by the National Science Foundation, was designed and is operated by Caltech and the Massachusetts Institute of Technology for the purpose of detecting gravitational waves, and for the development of gravitational-wave observations as an astronomical tool.</p><p>Research is carried out by the LIGO Scientific Collaboration, a group of 600 scientists at universities around the United States and in 11 foreign countries. The LIGO Scientific Collaboration interferometer network includes the LIGO interferometers (including the 2 km and 4 km detectors in Hanford, Washington, and a 4 km instrument in Livingston, Louisiana) and the GEO600 interferometer, located in Hannover, Germany, and designed and operated by scientists from the Max Planck Institute for Gravitational Physics and partners in the United Kingdom funded by the Science and Technology Facilities Council (STFC).</p><p>The next major milestone for LIGO is the Advanced LIGO Project, slated for operation in 2014. Advanced LIGO, which will utilize the infrastructure of the LIGO observatories, will be 10 times more sensitive. Advanced LIGO will incorporate advanced designs and technologies that have been developed by the LIGO Scientific Collaboration. It is supported by the NSF, with additional contributions from the U.K. STFC and the German Max Planck Gessellschaft.</p><p>The increased sensitivity will be important because it will allow scientists to detect cataclysmic events such as black-hole and neutron-star collisions at ten-times-greater distances and to search for much smaller "hills" on the Crab Pulsar.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.ligo.caltech.edu" class="pr-link">LIGO</a></div><div class="field-item odd"><a href="http://geo600.aei.mpg.de/" class="pr-link">GEO</a></div><div class="field-item even"><a href="http://www.ligo.org" class="pr-link">LIGO's Collaborators</a></div></div></div>Mon, 02 Jun 2008 14:00:00 +0000ksvitil1436 at http://www.caltech.eduAdvanced LIGO Project Funded by National Science Foundationhttp://www.caltech.edu/news/advanced-ligo-project-funded-national-science-foundation-1406
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Upgrade will enable the new field of gravitational wave astronomy</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kathy Svitil</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/icon.jpg?itok=GVhgKwLm" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.-- The Advanced LIGO Project, an upgrade in sensitivity for LIGO (Laser Interferometer Gravitational-wave Observatories), was approved by the National Science Board in its meeting on March 27. The National Science Foundation will fund the $205.12 million, seven-year project, starting with $32.75 million in 2008. This major upgrade will increase the sensitivity of the LIGO instruments by a factor of 10, giving a one thousand-fold increase in the number of astrophysical candidates for gravitational wave signals.</p><p>"We anticipate that this new instrument will see gravitational wave sources possibly on a daily basis, with excellent signal strengths, allowing details of the waveforms to be observed and compared with theories of neutron stars, black holes, and other astrophysical objects moving near the speed of light," says Jay Marx of the California Institute of Technology, executive director of the LIGO Laboratory.</p><p>Gravitational waves are ripples in the fabric of space and time produced by violent events in the distant universe--for example, by the collision of two black holes or by the cores of supernova explosions. Gravitational waves are emitted by accelerating masses much in the same way as radio waves are produced by accelerating charges-- such as electrons in antennas.</p><p>David Reitze of the University of Florida, spokesperson for the LIGO Scientific Collaboration, adds that "these ripples in the space-time fabric travel to Earth, bringing with them information about their violent origins and about the nature of gravity that cannot be obtained by other astronomical tools."</p><p>Albert Einstein predicted the existence of these gravitational waves in 1916 in his general theory of relativity, but only since the 1990s has technology become powerful enough to permit detecting them and harnessing them for science.</p><p>Although they have not yet been detected directly, the influence of gravitational waves on a binary pulsar system (two neutron stars orbiting each other) has been measured accurately and is in excellent agreement with the predictions. Scientists therefore have great confidence that gravitational waves exist. But a direct detection will confirm Einstein's vision of the waves, and allow a fascinating and unique view of cataclysms in the cosmos.</p><p>The Advanced LIGO detector, to be installed at the LIGO Observatories in Hanford, Washington, and Livingston, Louisiana, using the existing infrastructure, will replace the present detector, and will transform gravitational wave science into a real observational tool. David Shoemaker of MIT, the project leader for Advanced LIGO, says the "the improvement of sensitivity will allow the data set generated after one year of initial operations to be equaled in just several hours."</p><p>The change of more than a factor of 10 in sensitivity comes also with a significant increase in the sensitive frequency range, and the ability to tune the instrument for specific astrophysical sources. This will allow Advanced LIGO to look at the last minutes of life of pairs of massive black holes as they spiral closer, coalesce into one larger black hole, and then vibrate much like two soap bubbles becoming one.</p><p>It will also allow the instrument to pinpoint periodic signals from the many known pulsars that radiate in the range from 500 to 1000 Hertz (frequencies which correspond to high notes on an organ). Recent results from the Wilkinson Microwave Anisotropy Probe have shown the rich information that comes from looking at the photon, or infrared cosmic background, which originated some 400,000 years after the Big Bang. Advanced LIGO can be optimized for the search for the gravitational cosmic background--allowing tests of theories about the development of the universe only 10 to the minus 35 seconds after the Big Bang.</p><p>The LIGO Observatories were planned at the outset to support the continuing development of this new science, and the significant infrastructure of buildings and vacuum systems is left unchanged. The upgrade calls for changes in the lasers (180 watt highly stabilized systems), optics (40 kg fused silica "test mass" mirrors suspended by fused silica fibers), seismic isolation systems (using inertial sensing and feedback), and in how the microscopic motion (in the range of 10 to the minus 20 meters) of the test masses is detected.</p><p>Several of these technologies are significant advances in their fields, and have promise for application in a wide range of precision measurement, state-of-the-art optics, and controls systems. A program of testing and practice installation will allow the new detectors to be brought online with a minimum of interruption in observation. The instruments will be ready to start scientific operation in 2014.</p><p>The design of the instrument has come from scientists throughout the 50-institution, 600-person LIGO Scientific Collaboration, an international group that carries out both instrument development and scientific data analysis for LIGO. In the United States, these efforts (and in particular the LIGO Laboratory) are supported by the National Science Foundation (NSF).</p><p>"Advanced LIGO will be one of the most important scientific instruments of the 21st century. For the first time, it will let us listen in on the sounds of the universe, as unseen explosions, collisions, and whirlpools shake the fabric of space-time and send out the ripples that Advanced LIGO will measure. We in the German-British GEO project are excited that our long-standing partnership with LIGO allows us to contribute to Advanced LIGO some of the key technologies we have developed and tested in our GEO600 instrument," says Bernard F. Schutz, director of the Albert Einstein Institute in Germany.</p><p>The NSF funds the project through the Major Research Equipment and Facilities Construction (MREFC) budget account. The Caltech-MIT LIGO Laboratory will carry out the project.</p><p>Several international partners have already approved funding for significant contributions of equipment, labor, and expertise:</p><p>The UK contribution is the suspension assembly and some optics for the mirrors whose movements register the passage of the gravitational waves; this has been funded via Britain's Science and Technology Facilities Council (STFC).</p><p>The German contribution is the high-power, high-stability laser whose light measures the actual movements of the mirrors; this has been funded via the Max Planck Society in Munich.</p><p>The University of Florida and Columbia University are taking on specific responsibilities in the design and construction of Advanced LIGO.</p><p>Other members of the LIGO Scientific Collaboration (LSC), with NSF or other funding, will participate in all phases of the effort.</p><p>Photos are available at:</p><p><a href="http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResHanford_5.jpg">http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResHanfo...</a> <a href="http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResHanford_3.jpg">http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResHanfo...</a> <a href="http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResLivingston_5.jpg">http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResLivin...</a> <a href="http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResLivingston_6.jpg">http://www.ligo.caltech.edu/~beckett/LIGO_Images/HiResAerials/HiResLivin...</a></p><p>Additional information:</p><p>The LIGO Laboratory <a href="http://www.ligo.caltech.edu">http://www.ligo.caltech.edu</a>.</p><p>The LIGO Scientific Collaboration <a href="http://www.ligo.org">http://www.ligo.org</a>.</p><p>The National Science Foundation <a href="http://www.nsf.gov">http://www.nsf.gov</a>.</p><p>The Science and Technology Facilities Council <a href="http://www.scitech.ac.uk">http://www.scitech.ac.uk</a>.</p><p>The Max Planck Society <a href="http://www.mpg.de">http://www.mpg.de</a>.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.ligo.caltech.edu" class="pr-link">LIGO</a></div><div class="field-item odd"><a href="http://geo600.aei.mpg.de/" class="pr-link">GEO</a></div><div class="field-item even"><a href="http://www.ligo.org" class="pr-link">LIGO's Collaborators</a></div></div></div>Tue, 01 Apr 2008 14:00:00 +0000ksvitil1406 at http://www.caltech.eduLIGO Sheds Light on Cosmic Eventhttp://www.caltech.edu/news/ligo-sheds-light-cosmic-event-1367
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kathy Svitil</div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.-- An analysis by the international LIGO (Laser Interferometer Gravitational-Wave Observatory) Scientific Collaboration has excluded one previously leading explanation for the origin of an intense gamma-ray burst that occurred last winter. Gamma-ray bursts are among the most violent and energetic events in the universe, and scientists have only recently begun to understand their origins.</p><p>The LIGO project, which is funded by the National Science Foundation, was designed and is operated by the California Institute of Technology and the Massachusetts Institute of Technology for the purpose of detecting cosmic gravitational waves and for the development of gravitational-wave observations as an astronomical tool. Research is carried out by the LIGO Scientific Collaboration, a group of 580 scientists at universities around the United States and in 11 foreign countries. The LIGO Scientific Collaboration interferometer network includes the GEO600 interferometer, located in Hannover, Germany, funded by the Max-Plank-Gesellschaft/Science and Technologies Facilities Council and designed and operated by scientists from the Max Planck Institute for Gravitational Physics and partners in the United Kingdom.</p><p>Each of the L-shaped LIGO interferometers (including the 2-km and 4-km detectors in Hanford, Washington, and a 4-km instrument in Livingston, Louisiana) uses a laser split into two beams that travel back and forth down long arms, each of which is a beam tube from which the air has been evacuated. The beams are used to monitor the distance between precisely configured mirrors. According to Albert Einstein's 1916 general theory of relativity, the relative distance between the mirrors will change very slightly when a gravitational wave--a distortion in space-time, produced by massive accelerating objects, that propagates outward through the universe--passes by. The interferometer is constructed in such a way that it can detect a change of less than a thousandth the diameter of an atomic nucleus in the lengths of the arms relative to each other.</p><p>On February 1, 2007, the Konus-Wind, Integral, Messenger, and Swift gamma-ray satellites measured a short but intense outburst of energetic gamma rays originating in the direction of M31, the Andromeda galaxy, located 2.5 million light-years away. The majority of such short (less than two seconds in duration) gamma-ray bursts (GRBs) are thought to emanate from the merger and coalescence of two massive but compact objects, such as neutron stars or black-hole systems. They can also come from astronomical objects known as soft gamma-ray repeaters, which are less common than binary coalescence events and emit less energetic gamma rays.</p><p>During the intense blast of gamma rays, known as GRB070201, the 4-km and 2-km gravitational-wave interferometers at the Hanford facility were in science mode and collecting data. They did not, however, measure any gravitational waves in the aftermath of the burst.</p><p>That non-detection was itself significant.</p><p>The burst had occurred along a line of sight that was consistent with it originating from one of Andromeda's spiral arms, and a binary coalescence event--the merger of two neutron stars or black holes, for example--was considered among the most likely explanations. Such a monumental cosmic event occurring in a nearby galaxy should have generated gravitational waves that would be easily measured by the ultrasensitive LIGO detectors. The absence of a gravitational-wave signal meant GRB070201 could not have originated in this way in Andromeda. Other causes for the event, such as a soft gamma-ray repeater or a binary merger from a much further distance, are now the most likely contenders.</p><p>LIGO's contribution to the study of GRB070201 marks a milestone for the project, says Caltech's Jay Marx, LIGO's executive director: "Having achieved its design goals two years ago, LIGO is now producing significant scientific results. The nondetection of a signal from GRB070201 is an important step toward a very productive synergy between gravitational-wave and other astronomical communities that will contribute to our understanding of the most energetic events in the cosmos." "This is the first time that the field of gravitational-wave physics has made a significant contribution to the gamma-ray astronomical community, by searching for GRBs in a way that electromagnetic observations cannot," adds David Reitze, a professor of physics at the University of Florida and spokesperson for the LIGO Collaboration.</p><p>Up until now, Reitze says, astronomers studying GRBs relied solely on data obtained from telescopes conducting visible, infrared, radio, X-ray, and gamma-ray observations. Gravitational waves offer a new window into the nature of these events.</p><p>"We are still baffled by short GRBs. The LIGO observation gives a tantalizing hint that some short GRBs are caused by soft gamma repeaters. It is an important step forward," says Neil Gehrels, the lead scientist of the Swift mission at NASA's Goddard Space Flight Center.</p><p>"This result is not only a breakthrough in connecting observations in the electromagnetic spectrum to gravitational-wave searches, but also in the constructive integration of teams of complementary expertise. Our findings imply that multimessenger astronomy will become a reality within the next decade, opening a wonderful opportunity to gain insight on some of the most elusive phenomena of the universe," says Szabolcs Márka, an assistant professor of physics at Columbia University.</p><p>The next major construction milestone for LIGO will be the Advanced LIGO Project, which is expected to start in 2008. But Advanced LIGO, which will utilize the infrastructure of LIGO, will be 10 times more sensitive. Advanced LIGO will incorporate advanced designs and technologies for mirrors and lasers that have been developed by the GEO project and have allowed the GEO detector to achieve enough sensitivity to participate in this discovery despite its smaller size.</p><p>The increased sensitivity will be important because it will allow scientists to detect cataclysmic events such as black-hole and neutron-star collisions at 10-times-greater distances.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.ligo.caltech.edu" class="pr-link">LIGO</a></div><div class="field-item odd"><a href="http://geo600.aei.mpg.de/" class="pr-link">GEO</a></div></div></div>Wed, 02 Jan 2008 16:00:00 +0000ksvitil1367 at http://www.caltech.edu